PT-2026-40163 · Microsoft · Windows Ancillary Function Driver For Winsock+1

Angelboy + 1 · Published 2026-05-12 · Updated 2026-05-12 · CVE-2026-34344

Positive Technologies (AI Summary)

CVSS v3.1

7.8

High

Base vector

AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Name of the Vulnerable Software and Affected Versions Windows Ancillary Function Driver for WinSock (affected versions not specified)

Description A type confusion issue occurs when a resource is accessed using an incompatible type. This allows an authorized attacker to elevate privileges locally.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

LPE

Type Confusion

Weakness Enumeration

CWE-843

Related Identifiers

BDU:2026-06734

CVE-2026-34344

Affected Products

Windows

Windows Ancillary Function Driver For Winsock

References · 6

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-34344 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-34344 · Security Note
• https://msrc.microsoft.com/update-guide/en-US/advisory/CVE-2026-34344 · Vendor Advisory
• http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-34344 · Security Note
• https://bdu.fstec.ru/vul/2026-06734 · Security Note
• https://twitter.com/windowsforum/status/2054267210076496010 · Twitter Post